21980878 has 8 divisors (see below), whose sum is σ = 32998680. Its totient is φ = 10981320.

The previous prime is 21980857. The next prime is 21980897. The reversal of 21980878 is 87808912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 988 + ... + 6703.

It is an arithmetic number, because the mean of its divisors is an integer number (4124835).

Almost surely, 2^21980878 is an apocalyptic number.

21980878 is a deficient number, since it is larger than the sum of its proper divisors (11017802).

21980878 is a wasteful number, since it uses less digits than its factorization.

21980878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9122.

The product of its (nonzero) digits is 64512, while the sum is 43.

The square root of 21980878 is about 4688.3769046441. The cubic root of 21980878 is about 280.1227268120.

The spelling of 21980878 in words is "twenty-one million, nine hundred eighty thousand, eight hundred seventy-eight".